Make the rendering part of the build optional.

Add the mesa libs to the link line.

CMakeLists.txt

@@ -99,6 +99,7 @@ option(VTKm_ENABLE_BENCHMARKS "Enable VTKm Benchmarking" OFF)
 
 option(VTKm_BUILD_DOCUMENTATION "Build Doxygen documentation" OFF)
 option(VTKm_BUILD_EXAMPLES "Build examples" OFF)
+option(VTKm_BUILD_RENDERING "Build rendering" OFF)
 
 option(VTKm_USE_DOUBLE_PRECISION
   "Use double precision for floating point calculations"

vtkm/CMakeLists.txt

@@ -55,6 +55,12 @@ if(VTKm_ENABLE_OPENGL_INTEROP)
   add_subdirectory(opengl)
 endif(VTKm_ENABLE_OPENGL_INTEROP)
 
+#-----------------------------------------------------------------------------
+# Build rendering
+if(VTKm_BUILD_RENDERING)
+  add_subdirectory(rendering)
+endif(VTKm_BUILD_RENDERING)
+
 #-----------------------------------------------------------------------------
 #add the control and exec folders
 add_subdirectory(cont)
@@ -75,7 +81,3 @@ add_subdirectory(benchmarking)
 #-----------------------------------------------------------------------------
 #add the io folder
 add_subdirectory(io)
-
-#-----------------------------------------------------------------------------
-#add the rendering folder
-add_subdirectory(rendering)

vtkm/rendering/CMakeLists.txt

@@ -39,6 +39,5 @@ include_directories(${OSMESA_INCLUDE_DIR})
 
 
 
-
 #-----------------------------------------------------------------------------
 add_subdirectory(testing)

vtkm/rendering/testing/CMakeLists.txt

@@ -22,6 +22,6 @@ set(unit_tests
   UnitTestSceneRendererOSMesa.cxx
   UnitTestSceneRendererVolume.cxx
  )
- 
-VTKM_unit_tests(SOURCES ${unit_tests})
 
+VTKM_unit_tests(SOURCES ${unit_tests}
+                LIBRARIES ${OSMESA_LIBRARY})